The present invention relates to methods and devices useful for removing unwanted materials such as calculi, deposits and tissues from a body cavity.
Currently, urologists performing a procedure known as percutaneous nephrolithotomy (PCNL) often use a rigid nephroscope, a flexible cystoscope, or a flexible ureteroscope in conjunction with flexible baskets or graspers to remove stones and stone fragments from the renal cavity of a patient. A rigid or semi-rigid scope is often used to treat the lower urinary tract, while accessing upper urinary tract needs a flexible scope for negotiating the tortuosity when the ureter crosses the iliac vessels. Because of the high degree of deflexibility required for a scope to travel to the upper urinary tract, in terms of both active and passive deflection, adding accessories to the working channels of a flexible ureteroscope, which compromises the scope""s overall deflexibility, is often undesirable. See, Smith""s Textbook of Endourology, Vol. 1, Ch. 32 (1996, Quality Med. Pub. Inc.).
To remove stones and/or stone fragments, urologists generally use an endoscope coupled with accessories such as baskets or graspers. The use of accessories in the working channels of the endoscope becomes problematic when it comes to treating upper urinary tract because of added constraints on the scope""s deflexibility and hence access to the target. Also, using a basket or grasper through a flexible scope can be technically challenging due to the high level of manual dexterity required of an operator to manipulate effectively the basket or grasper to capture and retrieve the stone(s) and/or stone fragment(s). Procedures that use baskets or graspers also are time-consuming since the entire scope must be retracted to remove stone(s) or fragment(s) from the renal cavity. If there are multiple stone(s) or fragment(s) to be removed from a specific area, then every time a flexible scope is retracted, the urologist must maneuver his/her way back to the desired location to get the next stone or fragment. This obviously increases the level of tissue trauma to the patient and the risk of damage to the urinary tract.
Urologists also use lithotripters to crush stones into fragments that are passable through the urinary tract. Lithotripsy devices have been developed which utilize electrohydraulic probes, ultrasonic probes, electromechanical impactors, laser fibers and so on. An example of a lithotripter is a system known as xe2x80x9cLithoclastxe2x80x9d that is commercially available from Boston Scientific Corporation of Natick, Mass. Again, the addition of a lithotripter will compromise the scope""s deflexibility and thus will limit its use in treating the upper urinary tract. Such limitation also affects the breaking power of a lithotripter and renders treatment of upper urinary tracts longer and less successful.
Suction channels, sometimes with a lithotripter in a parallel working channel, have been integrated into scopes to help remove stones and fragments. For instance, a suction system known as xe2x80x9cLithovac,xe2x80x9d also available from Boston Scientific Corporation of Natick, Mass., can be matched with the xe2x80x9cLithoclastxe2x80x9d lithotripter system to remove stones and/or stone fragments from the renal cavity of a patient during a PCNL procedure. Because an integrated suction channel will further decrease the deflexibility of a flexible scope, the use of lithotripters with integrated suction is limited to renal areas that can be accessed by a rigid device. And even in such cases, the suction channel is often highly limited in its diameter and hence the suction capacity.
An object of the present invention is thus to provide an effective and efficient means for the removal of stones and other unwanted materials from cavities only accessible by a flexible endoscope, such as the upper urinary tract. A more general objective is to provide a suction means that can remove large targets and be suitable for treatment of all cavities in the body including those accessible by rigid instruments.
The present invention provides devices and related methods for the removal of unwanted materials such as calculi, deposits, tissues (e.g., polyps and tumor cells) and fluid from a patient""s (human or animal) body cavity. The invention achieves these objectives by providing a sleeve that is to be placed over an elongated instrument such as a flexible endoscope. The sleeve wall contains a port disposed between the distal opening and proximal opening; the port divides the lumen into a distal lumen and a proximal lumen. When the distal end of the inserted instrument is retracted beyond the port, a seal prevents direct passage of gas or liquid between the sleeve""s proximal opening and the port. Hence, a passageway is created between the sleeve""s distal opening and the port, and through a portion of the sleeve lumen. When the port is connected to a vacuum source, materials from a treatment site can be removed through the suction passageway. When the port is connected to a source of positive pressure (liquid or gas), it results in irrigation or ventilation of the treatment site through the sleeve""s passageway.
Because the passageway so created may have a cross-section as large as the entire cross-section of the sleeve, effective removal of large targets becomes possible. This maximization in the cross-section of the passageway offers a significant advantage over the removal capacity of known suction lumens that are integrated in a rigid, semi-rigid or flexible endoscope. Particularly for treatment of upper urinary tracts where scope deflexibility is crucial, the invention provides the possibility for a flexible scope containing a lithotripter in its working channels to also possess a suction function. The device of the invention also eliminates the need for using flexible forceps and flexible baskets through the working channels of flexible scopes, an operatively difficult and inefficient procedure for treating upper urinary tracts.
The time required to remove stones and their fragments is also substantially reduced with the excellent suction capability of the device of the invention. Because the sleeve remains positioned inside the body cavity, an operator can reinsert the instrument to the earlier position through the guidance of the sleeve. This saves the operator from re-performing the often time-consuming and technically-demanding procedure of maneuvering the medical instrument inside a body cavity such as the tortuous renal cavity. This also saves the patient from further discomfort and tissue trauma.
The sleeve is designed to receive an elongated medical instrument such as a scope and more particularly, a flexible scope such as a flexible cystoscope or a flexible ureteroscope. Therefore, the sleeve can take any shape to accommodate the shape of the instrument, and different segments of the sleeve may assume different shapes. The preferred shape of the sleeve is substantially cylindrical where a cross-section of the sleeve is substantially circular or oval. In a preferred embodiment, the port is connected to a vacuum pump. When the instrument is slid back until its distal end is proximal to the suction port, the space inside the sleeve previously occupied by the instrument becomes a suction passageway. Suction in the distal lumen is made possible by the presence of a seal in the sleeve""s proximal lumen. The seal may be in the form of an interference fit between the sleeve member and the instrument (e.g. around its radial surface).
The sleeve can have multiple lumens. Such lumens may be defined by a permanent partition integral with the sleeve, or by temporary structures that may be separated from the sleeve, or it may be created by the insertion of an instrument whose outer diameter is less then the inner diameter of the sleeve. At least one of these lumens may be connected to an aperture and serve as a channel for suction, irrigation or ventilation even when the distal end of the instrument is in the distal lumen. This aperture can be the same port that divides the sleeve lumen into the distal lumen and the proximal lumen. Alternatively, this aperture can be a separate opening.
The sleeve may be used to provide concurrent irrigation to the treatment site. This will prevent collapse of the renal cavity during suction by providing enough fluid flow to the renal cavity to counteract the suction force pulling material and fluid out of the renal cavity. A separate irrigation channel can also be integrated into the sleeve.
In some embodiments of the invention, the sleeve and the instrument are integrated into one unit. In other embodiments of the invention, the sleeve and the instrument are separable and the sleeve becomes disposable after use. This allows it to be manufactured inexpensively and does not require the operator to purchase any additional instrumentation in order to use the sleeve.
The wall forming the sleeve lumen may be made of a rigid, semi-rigid or flexible material. In a preferred embodiment where the sleeve is to enclose a flexible scope used for treating the upper urinary tract, the sleeve is made of flexible materials. As a result, the sleeve will not significantly impact the deflection capabilities of the flexible scope. In addition, the inner and/or outer surface of the sleeve may be coated partially or completely with a lubricious material to further reduce any impact on the deflexibility of the scope, allowing easy positioning and maneuvering around the renal cavity. In another embodiment, on the other hand, there may be structures such as reinforcement materials in the sleeve that prevents the sleeve from ovaling, kinking, or collapsing as a result of bending, manipulation, or suctioning of stone(s) or fragment(s).
The sleeve has a seal that prevents the direct passage of fluid between the port and the proximal opening of the sleeve. An example of the seal is an airtight connection with a portion of the enclosed instrument when the instrument is pulled back beyond the port. When the port is connected to a vacuum source, this seal in that segment of the sleeve allows the formation of a suction passageway from the sleeve""s distal opening to the suction port. An example of such a seal is a compressive clamp or an O-ring that tightens around the radial surface of the enclosed instrument. The instrument can also be force-fitted into the sleeve and the force-fitting remains proof when the distal end of the instrument is retracted into the proximal lumen. In that case, the seal comprises a portion of the sleeve""s inner surface that is in contact with the instrument. This seal may continue to prevent the direct passage of gas or liquid between the proximal opening and the port even when the distal end of the instrument is distal to the suction port. The seal may comprise a locked position and an unlocked position.
The port is connected to a source of pressurized fluid (gas or liquid), such as a pump. The source may generate negative pressure that causes suction, or it may generate positive pressure to inject fluid (such as saline solution or air). A switch, such as a trumpet valve assembly, may be used to switch the port between the suction mode and the injection mode. The port may be further connected to an on/off switch, and/or a pressure-regulator.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description, figures, and from the claims.